K3Ta3Si2O13 and Ba3Ta6Si4O26 particles prepared by a flux method using KCl possessed well-crystallized nanorod and block shapes, respectively. The K3Ta3Si2O13 and Ba3Ta6Si4O26 with one-dimensional and linear pillared structure showed photocatalytic activities for water splitting. The quantum yields were 2.4% and 0.2% at 254 nm for NiO/K3Ta3Si2O13 and NiO/Ba3Ta6Si4O26, respectively. The difference in the photocatalytic activity was related to the degree of distortion of the one-dimensional pillared structure.